The present invention relates to apparatuses for transporting objects and particularly to an object transport apparatus used for transporting objects with their cross sections different in size from each other.
A cable transport apparatus 101 as shown in FIGS. 24-26 has been employed for installing an electric cable by using a temporary overhead cable or for installing an electric cable in an underground pipe. This cable transport apparatus 101 is used as shown in FIG. 23 by being mounted on a support platform 210 that is placed on the lower part of a utility pole 160.
According to a method of using this cable transport apparatus 101 on an installation site, an electric cable 200 is transported by being successively fed to the left in FIG. 23 by cable transport apparatus 101 to the extent that tension is generated on electric cable 200 while electric cable 200 is hung on rings 180 provided on a temporarily installed overhead cable 170 that is suspended on respective top parts of poles 160. Then, electric cable 200 is removed from a pulley 220 when cable transport apparatus 101 causes electric cable 200 to fall in a state of tension, and this cable transport apparatus 101 is further used to successively feed electric cable 200 to the left by using a next pole (located further to the left of FIG. 23). This operation is repeated for each pole to accordingly install electric cable 200 on each pole. It is noted that a cable transport apparatus 2 used in a second embodiment of the present invention is employed in FIG. 23.
A structure of this cable transport apparatus 101 is now described in conjunction with FIGS. 24 and 25. As shown in FIGS. 24 and 25, cable transport apparatus 101 is constructed of a pedestal 110 and a transport unit 105. A power unit is provided within pedestal 110. Further, transport unit 105 has rotational axes 120a, 120b, 120c and 120d on a main surface of pedestal 110. Around rotational axes 120a, 120b, 120c and 120d, there are provided wheels 125a, 125b, 125c and 125d for conveying turning forces of rotational axes 120a, 120b, 120c and 120d and transport belts 140a and 140b for conveying turning forces of rotating wheels 125a, 125b, 125c and 125d by means of frictional forces on the peripheries of wheels 125a, 125b, 125c and 125d. 
In use of cable transport apparatus 101, a turning force of a motor causes wheels 125a and 125b to rotate about respective rotational axes 120a and 120b in opposite directions respectively. At this time, respective turning forces of wheels 125a and 125b are conveyed from the peripheries of wheels 125a and 125b to transport belts 140a and 140b respectively, and transport belts 140a and 140b then circulate respectively around wheels 125a and 125c and 125b and 125d. Frictional forces on the surface of circulating transport belts 140a and 140b feed electric cable 200 shown in FIG. 23 in the direction of transportation. At this time, wheels 125c and 125a rotate in the same direction while wheels 125d and 125b rotate in the same direction. Wheels 125b and 125d rotate in directions opposite to each other to assist transport belts 140a and 140b in circulating in opposite directions respectively.
A cable transport apparatus 102 as shown in FIGS. 27 and 28 is another cable transport apparatus having a transport unit structured differently from that of the above cable transport apparatus 101. Cable transport apparatus 102 includes as its transport unit spherical wheels 225a and 225b provided around rotational axes 220a and 220b as shown in FIGS. 27 and 28 on the main surface of pedestal 110 shown in FIG. 24 for conveying the turning force of the power unit. Spherical wheels 225a and 225b are formed of rubber containing therein air or the like, with their peripheral surfaces deformable according to the diameter of an electric cable. The electric cable is fed in a certain direction by a frictional force between spherical wheels 225a and 225b and the electric cable.
As for cable transport apparatus 101 shown in FIGS. 24 and 25, the distance W1 between rotational axes 120a and 120b and the distance W1 between rotational axes 120c and 120d are constant and thus the gap W2 between transport belts 140a and 140b is also constant. Therefore, if both of a thin cable 100 and a thick cable 200 are used simultaneously, cable transport apparatuses 101 should separately be prepared to be available all the time for respective thin cable 100 and thick cable 200 in order to employ the apparatuses according to need on an installation site.
If only one cable transport apparatus 101 is used for both of thin cable 100 and thick cable 200, cable transport apparatus 101 should have another mechanism capable of changing the distance W1 between rotational axes 120a and 120b and between axes 120c and 120d. 
If the diameter of thin cable 100 is smaller than the distance W2 between transport belts 140a and 140b, thin cable 100 could deviate in the direction of the arrows as shown in FIG. 25. Consequently, cable 100 could meander up and down between transport belts 140a and 140b as shown in FIG. 26 which results in a lower transport speed. Alternatively, if thin cable 100 significantly deviates in the direction of the arrow, thin cable 100 would escape from the part between transport belts 140a and 140b. 
For installation of a thick electric cable, usually a thin rope is first installed temporarily for drawing the thick cable to be installed actually, and the thick cable 200 is pulled via an adapter on the end of the rope having both ends to which respective ends of the rope and the cable with different diameters can be attached, the adapter having its diameter changing continuously. In this case, cable transport apparatus 101 should temporarily be stopped for replacing it with another cable transport apparatus having a greater distance between transport belts 140a and 140bon the installation site. Such a replacement of cable transport apparatus 101 on the installation site is laborious and deteriorates working efficiency.
Cable transport apparatus 102 shown in FIGS. 27 and 28 is employed as one conventional art for solving the problem above. Cable transport apparatus 102 includes spherical wheels 225a and 225b that deform according to the diameter of thin cable 100 and thick cable 200 in order to allow both of thin cable 100 and thick cable 200 to successively be fed without changing the distance W3 between rotational axes 220a and 220b, i.e., without employing another cable transport apparatus, and without employing any mechanism for changing the distance between rotational axes 220a and 220b. 
Although this cable transport apparatus 102 can transport an object or cable according to the diameter of the cable if the diameter is in a predetermined range, an extremely thin cable 100 could deviate in the directions indicated by the arrows shown in FIG. 27 because of the ball-like shape of spherical wheels 225a and 225b, so that cable 100 escapes from spherical wheels 225a and 225b. On the other hand, if cable 200 is thick enough to dramatically change the shape of spherical wheels 225a and 225b, spherical wheels 225a and 225b deform greatly to increase rotational resistance that hinders rotation of spherical wheels 225a and 225b. Consequently, the feeding speed of thick cable decreases. In order to reduce the rotational resistance, another mechanism should be provided for changing the distance W3 between rotational axes 220a and 220b as employed by cable transport apparatus 101.
The present invention is made to solve the problems above. One object of the present invention is to provide a cable transport apparatus for electric cables and the like, which can be applied to the case in which both of thin and thick electric cables are successively used, without the trouble of replacement of the apparatus on site and without escape of electric cables from the cable transport apparatus, and which can transport cables without reduction in cable transport speed.
An object transport apparatus according to one aspect of the invention transports an object by keeping contact with a part of the peripheral surface of the object and using frictional force between respective peripheral surfaces of at least two rotating transport members and the part of the peripheral surface of the object. The object transport apparatus includes the structure below.
Specifically, the object transport apparatus according to the one aspect of the invention includes a pedestal having continuing first and second surfaces with a predetermined angle therebetween, transport unit provided on the first and second surfaces respectively and keeping contact with a part of the peripheral surface of an object for transporting the object, and drive means for rotationally driving the transport unit in an object transport direction.
The transport unit includes first power transmission means having a plurality of first cylindrical members rotating about a plurality of rotational axes respectively that are substantially perpendicular to the first surface and in parallel with each other, second power transmission means having a plurality of second cylindrical members rotating about a plurality of rotational axes respectively that are substantially perpendicular to the second surface and in parallel with each other, and first and second belt-like transport members contacting or winding around respective peripheral surfaces of the first and second cylindrical members of respective first and second power transmission means to circulate respectively around the first and second power transmission means.
This structure allows the rotational axes to cross at a predetermined angle so that the first and second power transmission means form a V-shaped space between the first and second belt-like transport members. Accordingly, an object to be transported having a small diameter can be transported by keeping contact with the lower part of the V-shape and an object to be transported having a large diameter can be transported by keeping contact with the upper part of the V-shape, both of the objects being transported by frictional force generated between the objects and the first and second belt-like transport members. In this way, just the difference in dimension between the upper and lower parts of the V-shape can be increased for consecutively transporting objects having respective diameters ranging from smaller one to larger one, without addition of another mechanism and without replacement of the object transport apparatus.
Not only the first and second power transmission means but the first and second belt-like transport members are provided to increase the contact area with the object. The frictional force between the object and the first and second belt-like transport members is thus increased. Consequently, there is less possibility of idle rotation of the first and second power transmission means and thus the object can be transported in a more stable state.
More preferably, in the object transport apparatus according to the one aspect of the invention, the first belt-like transport member has one side, on the pedestal, of a transport surface contacting the object and the second belt-like member has one side, on the pedestal, of a transport surface contacting the object, respective one sides being in parallel and adjacent to each other.
This structure provides a reduced width of the gap between the first and second belt-like transport members, on the pedestal, in the V-shaped space formed by the first and second belt-like transport members. Accordingly, even if the object has a small diameter, the object can be prevented from escaping from the gap during transportation.
A cable transport apparatus according to another aspect of the invention transports an object by keeping contact with a part of the peripheral surface of the object and using frictional force between respective peripheral surfaces of at least two rotating transport members and the part of the peripheral surface of the object. The object transport apparatus includes the structure below.
Specifically, the cable transport apparatus according to the another aspect of the invention includes a pedestal having continuing first and second surfaces with a predetermined angle therebetween, transport unit provided on the first and second surfaces respectively and keeping contact with a part of the peripheral surface of an object for transporting the object, and drive means for rotationally driving the transport unit in an object transport direction.
The transport unit includes first power transmission means having a first cylindrical member rotating about a first rotational axis substantially perpendicular to the first surface, and second power transmission means having a second cylindrical member rotating about a second rotational axis crossing the first rotational axis and substantially perpendicular to the second surface.
This structure allows the first and second rotational axes to cross each other and thus form a V-shaped space between the first and second power transmission means. An object having a small diameter can be transported by keeping contact with the lower part of the V-shape and an object having a large diameter can be transported by keeping contact with the upper part of the V-shape. In this way, just the difference in dimension between the upper and lower parts of the V-shaped space can be increased for successively transporting objects having respective diameters ranging from smaller one to larger one, without additional mechanism and without replacement of the object transport apparatus.
More preferably, in the object transport apparatus according to the another aspect of the invention, the first cylindrical member as a component of the first power transmission means has one edge portion, on the pedestal, and the second cylindrical member as a component of the second power transmission means has one edge portion, on the pedestal, respective edge portions being adjacent to each other.
This structure provides a reduced gap on the pedestal between the first cylindrical transport member and the second cylindrical transport member in the V-shaped space formed by the first and second cylindrical transport members. It is thus possible to prevent an object being transported from escaping from the gap during transport even if the object has a small diameter.
The object transport apparatus according to the one aspect of the invention may further include object press means having a third cylindrical transport member with its peripheral surface pressing a transported object, the third cylindrical transport member being provided to be rotatable following transport of the object.
This structure has the object press means so that the object can be held without upward displacement in transport. At this time, the object press means rotates following the transport of the object and thus there is no remarkable reduction in cable transport speed. Even if the cable transport speed increases and the cable weaves in the V-shaped space, escape can be prevented of the cable from the V-shaped space between the first and second belt-like transport members. Stable transportation of an object is thus possible even if the transport speed of the object increases.
Still more preferably, the object transport apparatus according to the one aspect of the invention includes a plurality of object press means provided along a transport direction of an object.
This structure having a plurality of object press means enables an object to be transported more stably compared with the structure having one object press means.
Further, the object transport apparatus according to the one aspect of the invention preferably has the object press means including a support unit fixed to the pedestal and a press unit provided to turn around on one end of the support unit. The press unit can recede for stopping the press by being turned around.
In this structure, the press unit provided to turn around on one end of the support unit can recede for stopping the press. Therefore, in transport, loading and unloading of the object to and from the object transport apparatus is facilitated. The time required for installation on the site can accordingly be shortened.
The object transport apparatus according to the one aspect of the invention may have the object press means further including an external thread portion and an internal thread portion such that adjustment of the length of the external thread portion screwed into the internal thread portion allows the press unit to contact the object with an almost constant pressure.
In this structure, the object press means has the external thread portion which can be screwed into the internal thread to adjust the screwed length. Therefore, objects having respective diameters ranging from a smaller one to a larger one can be handled without replacement of the means. Consequently, reduction in installation time on the site is possible.
The object transport apparatus according to the one aspect of the invention may further include a third belt-like transport member circulating around the third cylindrical member following transport of the object while winding around or contacting the third cylindrical member.
The third belt-like transport member provided around the third cylindrical member allows the area of contact between the transported object and the object press means to achieve more stable transport of the object.
The drive mechanism of the object transport apparatus according to the invention includes a first spur gear and a first bevel gear rotating about a common rotational axis by a drive force, a second bevel gear engaging with the first bevel gear, a second spur gear engaging with the first spur gear, a third bevel gear rotating integrally about a rotational axis common to the second spur gear, and a fourth bevel gear engaging with the third bevel gear.
In this structure, the drive force causes the first spur gear to rotate which rotates the first bevel gear in the same direction, which is fixed by one shaft to the first spur gear, and accordingly the second bevel gear rotates. The second spur gear rotates in the direction opposite to the rotational direction of the first spur gear, and accordingly the third bevel gear rotates in the direction opposite to the rotational direction of the first bevel gear. Then, the fourth bevel gear rotates. Consequently, the second and fourth bevel gears rotate in the opposite directions respectively, in the state in which respective rotational axes of the first and second bevel gears cross each other with a predetermined angle therebetween in a plane perpendicular to the rotational axes of the first and the second spur gears and the first and second bevel gears, if the angle of inclination of the employed bevel gears is 45xc2x0. In this way, the V-shaped space can be formed between the first and second power transmission means respectively having the first and second cylindrical members rotating about respective rotational axes of the second and fourth bevel gears. It is thus possible to successively transport small-diameter and large-diameter objects by holding the objects in the V-shaped space.
According to a method of using the object transport apparatus of the invention, the object transport apparatus of the one aspect of the invention discussed above is used by moving the apparatus up and down along a long pole-like object standing substantially perpendicularly to the ground. The object transport apparatus holds the long object with a predetermined press force at three portions, i.e., by the first and second belt-like transport members and the object press means, and the drive means is rotationally driven to move the object transport apparatus up and down along the long object by frictional force between the first and second belt-like members and the object press means and the long object.
The object transport apparatus according to the one aspect of the invention is used by such a method to enable the object transport apparatus to move up and down along an object to be transported, by the frictional force between the first and second cylindrical transport members or the first and second belt-like transport members and the object. Electric cable, safety rope, tools and the like, for example, can thus be conveyed to the top of a pole without human force.
According to a method of using the object transport apparatus of the invention, two object transport apparatuses of the type according to the one aspect of the invention may be used. The two object transport apparatuses are made opposite to each other such that respective sides contacting a transported object face each other, each side belonging to the first and second belt-like transport members. The object transport apparatuses are moved up and down along a long pole-like object standing perpendicularly to the ground by holding the long object between the first and second belt-like transport members of the two object transport apparatuses and rotationally driving the drive means to use frictional force of the transport members for moving the object transport apparatuses.
By this method of using the object transport apparatus according to the first aspect of the invention, the frictional force between the transported object and the first and second cylindrical transport members or the first and second belt-like transport members of the object transport apparatus can be used to move the object transport apparatus up and down along the long object. Cable, safety rope, tools and the like, for example, can thus be conveyed to the top of a pole without human force. In addition, two object transport apparatuses can be used to allow respective first and second cylindrical transport members or the first and second belt-like transport members to contact the transported object and thus the frictional force is increased compared with the contact of the three point, i.e., the object press means and the first and second cylindrical transport members or the first and second belt-like transport members. Therefore, even an object having a great weight can be moved up and down along the long object.
According to the method of using the object transport apparatus of the invention, in addition to the object transport apparatus of the first aspect of the invention, another object transport apparatus having the structure of that object transport apparatus of the first aspect may be used such that the object transport apparatuses are fixed with respective transport directions of the transport units being substantially perpendicular to each other and accordingly the another object transport apparatus transports an object substantially perpendicularly to the long object.
This method of use can be employed to move the object transport apparatus to the upper part of the long object and then transport an object substantially perpendicularly to the long object. In this way, a cable or the like can be installed, for example, on each pole by lifting the cable to the top of the pole and then transporting the cable perpendicularly to the pole. It is thus unnecessary for a person carrying a cable to climb to the top of the pole in order to install the cable.
More preferably, according to the method of using the object transport apparatus of the invention, the ratio between respective rotational speeds of the first and second power transmission means is changed to move the object transport apparatus in a helical manner up and down along the long object.
This method of use enables a rope or cable to be wound helically around the long object. A rope or the like can helically be wound around a pole or the like, for example, in order to prevent the rope from swaying due to blowing wind.